In order to characterize the present invention over the prior art, reference is made to existing valves on water jet propulsion systems that are used for steering and positioning a water craft:
U.S. Pat. No. 3,132,477 issued to J. C. Egger on May 12, 1964;
U.S. Pat. No. 3,176,648 issued to M. Cavero on Apr. 6, 1965;
U.S. Pat. No. 3,492,965 issued to D. J. Wayfield on Feb. 3, 1970;
U.S. Pat. No. 3,675,611 issued to J. P. Glass on Jul. 11, 1972;
U.S. Pat. No. 4,265,192 issued to G. L, Dunn on May 5, 1981;
U.S. Pat. No. 5,014,912 issued to D. A. Brooks on May 14, 1991;
U.S. Pat. No. 5,129,846 issued to B. A. Dimijian on Jul. 14, 1992.
The valve systems described in the above-mentioned documents have multiple outlet ports that are controlled by mechanical actuators. These systems also comprise a pump and a valve cluster that are located inside the boat. The nozzles extend at a shallow depth under the boat where water pressure at the nozzles is negligible. These systems are designed for above-water operation, basically.
U.S. Pat. No. 7,124,698 issued to Y. T. Shen et al. on Oct. 24, 2006; describes a maneuvering system for a submarine. A pump draws water from one end of a tube and forces this water to an outlet at the other end of the tube. The outlet is oriented in such a way to steer the water craft. The system is controlled by gate valves operated by mechanical actuators. The pump and the valve actuators need to be sealed from deep water pressure to prevent damage.
Although the systems of the prior art deserve undeniable merits, it is believed that there is a need in the marine industry for an underwater thruster and guidance system that is easy to manufacture and that is more appropriate for use in remotely operated vehicles in deep sea applications.